The present invention relates to an adjustable connector assembly for a prosthetic limb, for example, of the general type disclosed in U.S. Pat. No. 6,033,440, the disclosure of which is incorporated by reference. FIGS. 1A and 1B of this patent disclose a conventional pyramidal boss connector or link plate 10, and a similar pyramidal connector or bracket 55 is disclosed in FIGS. 1 and 4 of U.S. Pat. No. 6,106,559 which is assigned to the assignee of the present invention. FIGS. 2-10 of above-mentioned U.S. Pat. No. 6,033,440 disclose an adjustable pyramidal link plate assembly which incorporates a rotatable four sided boss wedged within a slide confined within a dovetail slot held by laterally projecting set screws. The assembly is adapted to be used when a prosthetic leg is not properly aligned with an amputee""s residual limb or stump and provides for lateral adjustment as well as rotatable adjustment of the artificial leg relative to the stump and socket. Another form of adjustable pyramid connector is disclosed in U.S. Pat. No. 6,013,105. This connector also provides for sliding and rotating the pyramidal boss with the use of a an undercut slot and a central locking screw extending through the boss into a nut slidable with the slot.
The present invention is directed to an improved adjustable connector assembly for a prosthetic limb and which also provides for lateral and rotational adjustment. In addition, the adjustable connector assembly of the invention provides for substantial strength and rigidity after adjustment. In one form, the connector has a projecting four sided pyramidal boss and in another form, has an annular collar for receiving such a boss. The connector assembly of the invention may also be efficiently and economically constructed from solid titanium bar stock on a numerically controlled machine tool in order to provide the assembly with compactness and low weight in addition to high strength.
In accordance with a preferred embodiment of the invention, a circular base member or plate is formed with a flat base surface and a pair of generally parallel spaced and integral track portions. Countersink holes are formed from the base surface through the base plate for attaching the base plate, for example, to a coupler mounted within the bottom portion of a socket which receives the residual limb portion. A circular connector member has an outwardly projecting circular base flange which fits between the track portions of the base plate, and the base flange is rigidly secured or clamped to the base plate by a pair of opposing clamping rails each of which is secured to the base plate by a set of socket head machine screws extending into the corresponding track portion.
In one embodiment, the connector member has a dome surface projecting from the base flange and a projecting four sided pyramidal boss with undercut surfaces for engagement by the ends of set screws extending, for example, through threaded holes within an annular adaptor for a prosthetic leg pylon. In another embodiment, the connector member includes an annular collar projecting from the annular base flange for receiving a four sided pyramidal boss. The collar has circumferentially-spaced threaded holes through which set screws extend for engaging the undercut surfaces of the pyramidal boss.